Heating and cooling air conditioning system



Sept. 8, 1964 MlNER 3,147,797

HEATING AND CQOLING AIR CONDITIONING SYSTEM Filed April 7, 1961 2 Sheets-Sheet 1 INVENTOR.

ROBERT G. M IN ER WwW A T T O R N E YS FIG.

p 8, 1964 R. G. MINER 3,147,797

HEATING AND COOLING AIR CONDITIONING SYSTEM Filed April 7, 1961 2 Sheets-Sheet 2 cu P5 ;2' LL 0 o 2 cu INVENTOR,

ROBERT G. MINER ATTORNEYS United States Patent 3,147,797 HEATHNG AND CGGLHNG AER CQNDITHBNING SYSTEM Robert G. Miner, La Crosse, Wis, assignor to The Trane Company, La Crosse, Wis, corporation of Wisconsin Filed Apr. 7,1961, Ser. No. 101,411 5 Claims. (Cl. 165-42) This invention relates to air conditioning and more particularly to a heating and cooling system for a building having a plurality of zones.

An object of the invention is to provide an improved heating and cooling system having a supply of hot fluid and a supply of cold fluid available to the units of the zones and having means for returning the fluid from a particular zone to the hot supply when the flow of hot fluid to the zone exceeds a predetermined portion of the total flow and having means for returning the fluid from the zone to the cold supply when the flow of cold fluid to the zone exceeds a predetermined portion of the tmal flow.

It is another object of the invention to cool the returned cold fluid in the evaporator of a refrigeration machine and to heat the returned hot fluid in the condenser of the refrigeration machine or in a heater or in both the condenser and the heater.

It is another object of the invention to provide in this system, automatic means to deliver hot fluid or cold fluid to the units according to the demand for heating or cooling in the space served by the unit and to vary the magnitude of flow of hot fluid or cold fluid according to the magnitude of deviation in temperature from the control temperature.

Other objects of the invention will become apparent as the specification proceeds to describe the invention with reference to the accompanying drawings in which:

FIGURE 1 is a diagrammatic view illustrating the air conditioning system of the present invention;

FIGURE 2 is a diagrammatic view on an enlarged scale of that portion of the system which controls the flow of fluid from each zone to the return mains.

Referring now to FIGURE 1, the system is shown as having two zones and 12. Air conditioning units 14 are mounted in the zones. Although two zones have been shown with two units in each zone, it is obvious tha a system may have more than two zones and a zone may have more than two units.

A compressor 16, a condenser 18, and an evaporator 29 are connected to form a refrigeration machine for maintaining a supply of hot fluid and a supply of cold fluid.

The compressed gas discharged by the compressor 16 is conducted to the condenser 18 through conduit 22, the condensed refrigerant is conducted from the condenser 18 to the evaporator 20 through conduit 24. The usual expansion device 26 controls the flow in the conduit 24. A suction conduit 28 conducts the refrigerant gas from the evaporator 20 to the compressor 16.

The cold fluid circuit has a main return conduit 31) from the zones 10 and 12. A pump 32 is connected to the main return conduit 3i) and circulates the cold fluid through evaporator 20 to the main cold fluid supply conduit 34. A conduit 36 is connected from the conduit 34 at a point adjacent to and downstream of the evaporator 21 to a differential pressure relief valve 355. A conduit 40 is connected from the valve 38 to the return conduit 30 at a point adjacent to and upstream of the pump 32. The pressure relief valve 38 opens when the pressure difference between the conduits 34 and 3d exceeds a predetermined amount. In this manner there is always a predetermined minimum flow of fluid through the evapice orator 20 even though there is no flow or substantially no flow to the zones through conduit 34.

The hot fluid circuit has a main return conduit 42 from the zones 15} and 12. A pump 44 is connected to conduit 42 and circulates the hot fluid through condenser 13, thence through heater 46 and finally into a main hot fluid supply conduit 48. The heater 4-6 may be heated by steam or it may be a fired hot water boiler.

The hot fluid return 42 and the cold fluid return 30 are connected to an expansion tank 49 which receives any excess fluid from either the hot or the cold fluid circuits.

The condenser 18 receives cooling fluid from a source 50 and the cooling fluid is returned to the source or wasted through conduit 52. A valve 51 in conduit 59 has a pressure sensing tap 53 connected to the discharge conduit 22. Valve 51 operates to supply to the condenser only sufficient cooling fluid to prevent the discharge pres sure from exceeding a predetermined amount.

The zones each have a hot fluid supply conduit 54 connected to the main hot fiuid supply conduit 48. Each zone also has a cold fluid supply conduit 56 connected to the main cold fluid supply conduit 34.

Each of the units 14 has a valve 53 which controls the flow of cooling fluid to the heat exchange coil 60 in the unit. The valves 58 have a temperature sensing bulb -52 in the air of the area served by the unit. Each valve 58 is connected to and receives hot fluid through conduit 64 which is connected to receive hot fluid from conduit 54. Each valve 5% is also connected to and receives cold fluid through conduit 66 which is connected to receive cold fluid from conduit 56.

The valve 58 is constructed to pass but fluid to the coil 68 when the temperature of the area served falls below a first predetermined temperature and the rate of flow is increased according to the amount that the temperature of the area is below the first predetermined temperature. The valve 58 is constructed to pass cold fluid to the coil 68 when the temperature of the area served rises above a second predetermined temperature and the rate of flow of cold fluid is increased according to the amount that the temperature of the area is above the second predetermined temperature. The second predetermined temperature is a few degrees above the first predetermined temperature so that when the temperature of the area is between the two predetermined temperatures, the valve 58 passes neither hot nor cold fluid.

The fluid from the coils 60 of a zone flows through a conduit 68 to a three way valve 70. The valve '70 is connected by conduit 72 to the main hot fluid return 42 and by conduit 74- to the main cold fluid return 30.

The construction and operation of the valve 76 will be described with reference to FIGURE 2. The valve 79 has a port 75 for hot fluid and a port 76 for cold fluid. A valve stem 78 has a first valve plug 8d which cooperates with port 75 and a second valve plug 82 cooperates with port 76. The valve stem 78 is secured to a flexible diaphragm 84-. The pressure above the diaphragm 84 acting against a spring 36 determines the position of the valve stem 78. The pressure above the diaphragm 84 is varied through the conduit 88. The means for varying the pressure in conduit 88 will now be described.

A differential pressure sensing device 89 has a flexible diaphragm 9t] separating chambers 91 and 92. Chamber 91 is connected by conduit 93 to a point in conduit 54 upstream of orifice 94. Chamber 92 is connected by conduit 95 to a point downstream of orifice 94. A second flexible diaphragm 96 separates chamber 97 from chamher 98. Chamber 97 is connected by conduit 98 to conduit 56 at a point downstream of orifice 99. Chamber 98 is connected by conduit 10%) to conduit ss at a point upstream of orifice 99. Diaphragms and 96 are both mounted on a rod 102. A flexible diaphragm 104 is secured to rod 192 and closes chamber 91. A flexible diaphragm 106 is secured to rod 102 and closes chambers 92 and 97. A flexible diaphragm 168 is secured to shaft 102 and closes chamber 98. A flapper 110 is pivoted at 112 and cooperates with a leak port 113 in the end of conduit 114. A spring 116 acts on flapper 110 to hold it against the rod 102.

When the flow in conduit 56 becomes greater than the flow in conduit 54, the force urging diaphragm 96 to the right becomes greater than the force urging the diaphragm 91 to the left. Therefore rod 102 moves to the right and allows flapper 110 to move toward leak port 113 to reduce the leakage from conduit 114. When the flow in conduit 54 becomes greater than the flow in conduit 56 flapper 110 moves away from leak port 113 and the pressure in conduit 114 is reduced.

A relay 119 has a chamber 117 which is connected by conduit 118 to a source of fluid pressure 120. Leading from chamber 117 is a passageway 122 to an adjustable flow restricting valve 124. A passageway 126 leads from valve 124 to chamber 128. Chamber 128 is in fluid communication with conduit 114. A valve member 115 determines the flow of fluid from chamber 117 through a port 130 to a chamber 132. A spring 133 urges valve member 115 toward closed position with respect to port 130. A spool 134 is secured at one end to a flexible diaphragm 136 and at the other end to a flexible diaphragm 138. Spool 134 has a port 140 which cooperates with the upper end of valve member 15 to control the flow of fluid from chamber 132 to the atmosphere through an opening 142. A spring 144- urges the spool 134 in a direction away from the valve member 115.

The operation of the entire control mechanism of FIG- URE 2 will now be described. Assume that the flow of cold fluid in conduit 56 is greater than the flow of hot fluid in conduit 54 for a particular zone. Under these conditions, as explained above, the flapper 119 is close to the leak port 113 and the pressure in conduit 114 and chamber 123 is high. The high pressure in chamber 128 means that spool 134 is forced to its downward position closing port 140 and holding valve member 115 away from port 130. With port 139 open, the pressure 1n chamber 132 and in conduit 88 is substantially the full pressure of the supply 126. With full pressure above the diaphragm 84 of the valve 70, the valve stem 73 is in its down position, and valve plug 80 is in closed position with respect to port 75. In this position of the valve stem 73, valve plug 82 is in open position with respect to valve port 76 and all of the fluid flowing from the Zone through conduit 68 is directed to conduit 74 and thence to the cold fluid main return conduit 30. It is thus seen that when the flow of cold fluid to a zone is greater than the flow of hot fluid, valve '70 returns the water to the cold fluid return conduit 31).

Assume now that the flow of hot fluid to a zone is greater than the flow of cold fluid to that zone, as explained above the flapper 110 of diflerential pressure sensing device 39 will be away from the leak port 113 and the pressure in conduit 114 and chamber 128 will be relatively low. With a low pressure in chamber 128, spring 144 holds spool 134 away from the valve member 115, and spring 133 holds valve member 115 in closed position with respect to port 130. The fluid in chamber 132 and conduit 88 is vented to the atmosphere through port 140 and opening 142. The absence of pressure in conduit 88 means that there is no pressure above the diaphragm of the valve 70. Consequently the spring 86 of the valve 70 holds the valve stem 78 in its upward position with port '75 open and port 76 closed. It is thus seen that where the hot fluid flow to a zone exceeds the cold fluid How to that zone, the valve 70 returns the fluid from that zone to conduit 72 and thence to the main hot fluid return conduit 42.

Although I have shown and described a specific embodiment of my invention, it is apparent that changes may be made without departing from the spirit or scope of my invention, and therefore I desire to be limited only by the claims.

I claim:

1. An air conditioning system for a space having a plurality of zones with each zone having a plurality of areas with similar heating and cooling requirements, a source of hot fluid, a source of cold fluid, a first conduit connected to said source of hot fluid for conducting hot fluid from said source of hot fluid to the zones, a second conduit connected to said source of cold fluid for conducting cold fluid from said source of cold fluid to the zones, a third conduit connected to said source of hot fluid for conducting hot fluid from the zones back to said source of hot fluid, a fourth conduit connected to said source of cold fluid for conducting cold fluid from the zones back to said source of cold fluid, units for each zone for heating and cooling the areas of the zones, a fifth conduit connected to said first conduit and to the units of a first zone for conducting hot fluid from said first conduit to units of a first zone, a sixth conduit connected to said second conduit and to the units of said first zone for conducting cold fluid from the second conduit to units of said first zone, a common return conduit connected to the units of said first zone for conducting fluid from the units of said first zone, valve means for putting said common return conduit in fluid communication with said third conduit or said fourth conduit, means for comparing the volume rates of flow in said fifth and sixth conduits, and means responsive to said last mentioned means for controlling said valve means to put said common return conduit in fluid communication with said third conduit when the volume rate of flow in said fifth conduit exceeds a predetermined proportion of the volume rate of flow in said sixth conduit and to put said common return conduit in fluid communication with said fourth conduit when the volume rate of flow in said sixth conduit exceeds a predetermined proportion of the volume rate of flow in said fifth conduit.

2. An air conditioning system for a space having a plurality of zones with each zone having a plurality of areas with similar heating and cooling requirements, a source of hot fluid, a source of cold fluid, a first conduit connected to said source of hot fluid for conducting hot fluid from said source of hot fluid to the zones, a second conduit connected to said source of cold fluid for conducting cold fluid from said source of cold fluid to the zones, a third conduit connected to said source of hot fluid for conducting hot fluid from the zones back to said source of hot fluid, a fourth conduit connected to said source of cold fluid for conducting cold fluid from the zones back to said source of cold fluid, units for each zone for heating and cooling the areas of the zones, a fifth conduit connected to said first conduit and to the units of a first zone for conducting hot fluid from said first conduit to units of a first zone, a sixth conduit connected to said second conduit and to the units of said first zone for conducting cold fluid from the second conduit to units of said first zone, a common return conduit connected to the units of said first zone for conducting fluid from units of said first zone, valve means connected to and in fluid communication with said common return conduit, said third conduit and said fourth conduit, means for actuating said valve means to put said common return conduit in fluid communication with said third conduit or said fourth conduit, a first orifice in said fifth conduit, a second orifice in said sixth conduit, means for opposing the pressure drop across said first orifice against the pressure drop across said second orifice, means responsive to said last mentioned means for controlling said valve actuating means to put said common return conduit in fluid communication with said third conduit when the pressure drop across said first orifice exceeds a predetermined proportion of the pressure drop across said second orifice and to put said common return conduit in fluid communication with said fourth conduit when the pressure drop Jun across said second orifice exceeds a predetermined proportion of the pressure drop across said first orifice.

3. An air conditioning system for a space having a plurality of zones with each zone having a plurality of areas with similar heating and cooling requirements, a source of hot fluid, a source of cold fluid, a first conduit connected to said source of hot fluid for conducting hot fluid from said source of hot fluid to the zones, at second conduit connected to said source of cold fluid for conducting cold fluid from said source of cold fluid to the zones, a third conduit connected to said source of hot fluid for conducting hot fluid from the zones back to said source of hot fluid, a fourth conduit connected to said source of cold fluid for conducting cold fluid from the zones back to said source of cold fluid, units for each zone for heating and cooling the areas of the zones, valves for controlling the flow of hot fluid and cold fluid to the units of a first zone, means for controlling said valves responsive to temperatures in the areas served by said units, a fifth conduit connected to said first conduit and to said valves for conducting hot fluid from said first conduit to said valves, a sixth conduit connected to said second conduit and to said valves for conducting cold fluid from the second conduit to said valves, a common return conduit connected to the units of said first zone for conducting fluid from the units of said first zone. valve means for putting said common return conduit in fluid communication with said third conduit or said fourth conduit, means for comparing the volume rates of flow in said fifth and sixth conduits, and means responsive to said last mentioned means for controlling said valve means to put said common return conduit in fluid communication with said third conduit when the volume rate of flow in said fifth conduit exceeds a predetermined proportion of the volume rate of flow in said sixth conduit and to put said common return conduit in fluid communication with said fourth conduit when the volume rate of flow in said sixth conduit exceeds a predetermined proportion of the volume rate of flow in said fifth conduit.

4. An air conditioning system for a space having a plurality of zones with each zone having a plurality of areas with similar heating and cooling requirements, a source of hot fluid, a source of cold fluid, a first conduit connected to said source of hot fluid for conducting hot fluid from said source of hot fluid to the zones, a second conduit connected to said source of cold fluid for conducting cold fluid from said source of cold fluid to the zones, a third conduit connected to said source of hot fluid for conducting hot fluid from the zones back to said source of hot fluid, a fourth conduit connected to said source of cold fluid for conducting cold fluid from the zones back to said source of cold fluid, units for each zone for heating or cooling the areas of the zones, a fifth conduit connected to said first conduit and to the units of a first zone for conducting hot fluid from said first conduit to units of a first zone, a sixth conduit connected to said second conduit and to the units of said first zone for conducting cold fluid from the second conduit to units of said first zone, a common return conduit connected to the units of said first zone for conducting fluid from units of said first zone, valve means connected to and in fluid communication with said common return conduit, said third conduit and said fourth conduit, means for actuating said valve means to put said common return conduit in fluid communication with said third conduit or said fourth conduit, a first rate of flow sensing means in said fifth conduit for producing a pressure proportional to the rate of flow in said fifth conduit, a second rate of flow sensing means in said sixth conduit for producing a pressure proportional to the rate of flow in said sixth conduit, fluid pressure responsive means for opposing the pressures produced by said first and second rate of flow sensing means, and means responsive to said fluid pressure responsive means for controlling said valve actuating means to put said common return conduit in fluid communication with said third conduit when the rate of flow in said fifth conduit exceeds a predetermined proportion of the rate of flow in said sixth conduit and to put said common return conduit in fluid communication with said fourth conduit when the rate of flow in said sixth conduit exceeds a predetermined proportion of the rate of flow in said fifth conduit.

5. An air conditioning system for a space having a plurality of zones With each zone having a plurality of areas with similar heating and cooling requirements, a source of hot fluid, a source of cold fluid, a first conduit con nected to said source of hot fluid for conducting hot fluid from said source of hot fluid to the zones, a second conduit connected to said source of cold fluid for conducting cold fluid from said source of cold fluid to the zones, a third conduit connected to said source of hot fluid for conducting hot fluid from the zones back to said source of hot fluid, a fourth conduit connected to said source of cold fluid for conducting cold fluid from the zones back to said source of cold fluid, units for each zone for heating and cooling the areas of the zones, valves for controlling the flow of hot fluid and cold fluid to the units of a first zone, means for conrtolling said valves responsive to a temperature in the areas served by said units, a fifth conduit connected to said first conduit and to said valves for conducting hot fluid from said first conduit to said valves, a sixth conduit connected to said second conduit and to said valves for conducting cold fluid from the second conduit to said valves, a common return conduit connected to the units of said first zone for conducting fluid from units of said first zone, valve means in fluid communication with said return conduit, said third conduit and said fourth conduit, means for actuating said valve means to put said common return conduit in fluid communication with said third conduit or said fourth conduit, a first orifice in said fifth conduit, a second orifice in said sixth conduit, means for opposing the pressure drop across said first orifice against the pressure drop across said second orifice, means responsive to said last mentioned means for controlling said valve actuating means to put said common return conduit in fluid communication with said third conduit when the pressure drop across said first orifice exceeds a predetermined proportion of the pressure drop across said second orifice and to put said common return conduit in fluid communication with said fourth conduit when the pressure drop across said second orifice exceeds a predetermined proportion of the pressure drop across said first orifice.

References Cited in the file of this patent UNITED STATES PATENTS 2,115,706 Cornell May 3, 1938 2,216,245 Larson Oct. 1, 1940 2,796,740 McFarlan June 25, 1957 2,868,461 Gaddis Ian. 13, 1959 2,915,298 Hamlin et a1. Dec. 1, 1959 2,935,857 McFarlan May 10, 1960 2,942,785 Arbogast June 28, 1960 3,024,008 Blum Mar. 6, 1962 

1. AN AIR CONDITIONING SYSTEM FOR A SPACE HAVING A PLURALITY OF ZONES WITH EACH ZONE HAVING A PLURALITY OF AREAS WITH SIMILAR HEATING AND COOLING REQUIREMENTS, A SOURCE OF HOT FLUID, A SOURCE OF COLD FLUID, A FIRST CONDUIT CONNECTED TO SAID SOURCE OF HOT FLUID FOR CONDUCTING HOT FLUID FROM SAID SOURCE OF HOT FLUID TO THE ZONES, A SECOND CONDUIT CONNECTED TO SAID SOURCE OF COLD FLUID FOR CONDUCTING COLD FLUID FROM SAID SOURCE OF COLD FLUID TO THE ZONES, A THIRD CONDUIT CONNECTED TO SAID SOURCE OF HOT FLUID FOR CONDUCTING HOT FLUID FROM THE ZONES BACK TO SAID SOURCE OF HOT FLUID, A FOURTH CONDUIT CONNECTED TO SAID SOURCE OF COLD FLUID FOR CONDUCTING COLD FLUID FROM THE ZONES BACK TO SAID SOURCE OF COLD FLUID, UNITS FOR EACH ZONE FOR HEATING AND COOLING THE AREAS OF THE ZONES, A FIFTH CONDUIT CONNECTED TO SAID FIRST CONDUIT AND TO THE UNITS OF A FIRST ZONE FOR CONDUCTING HOT FLUID FROM SAID FIRST CONDUIT TO UNITS OF A FIRST ZONE, A SIXTH CONDUIT CONNECTED TO SAID SECOND CONDUIT AND TO THE UNITS OF SAID FIRST ZONE FOR CONDUCTING COLD FLUID FROM THE SECOND CONDUIT TO UNITS OF SAID FIRST ZONE, A COMMON RETURN CONDUIT CONNECTED TO THE UNITS OF SAID FIRST ZONE FOR CONDUCTING FLUID FROM THE UNITS OF SAID FIRST ZONE, VALVE MEANS FOR PUTTING SAID COMMON RETURN CONDUIT IN FLUID COMMUNICATION WITH SAID THIRD CONDUIT 